KR100310740B1 - Biodegradable thermoplastics and packaging materials made from them - Google Patents

Abstract

PCT No. PCT/DE95/01732 Sec. 371 Date Jun. 6, 1997 Sec. 102(e) Date Jun. 6, 1997 PCT Filed Dec. 6, 1995 PCT Pub. No. WO96/17888 PCT Pub. Date Jun. 13, 1996Biodegradable thermoplastic materials made of blends of starch esters and polyalkylene glycols with additions of polybasic aliphatic carboxylic acids and oxycarboxylic acids are improved with respect to water stability and mechanical characteristics and barrier properties by admixing to the blends aliphatic polycarbonates at levels of from 5:95 to 95:5 with the optional addition of ecologically compatible plasticizers and fillers. These materials can be used for all goods which are to be packaged in films, in particular tobacco products, but also soap, paper tissues, toilet articles, and the like. In addition to biodegradability, said materials are characterized in that they may be fed to a special recycling process, but also to conventional recycling processes without adversely affecting them.

Description

[Name of invention]

Biodegradable thermoplastics and packaging materials made from them

[Technical Field]

The present invention relates to thermoplastics made from biodegradable polymer blends in the form of granules, mold parts, extruded products, films and the like, based on blends comprising starch esters, polyalkylene glycols and other biologically compatible additives. And to a packaging made from the biodegradable thermoplastics.

[Background]

As environmental pollution becomes a problem, there is an increasing demand for ecologically compatible materials in the polymer market. In view of this, the result is the use of products from polyester, polyvinyl alcohol, starch and low-substituted starch derivatives, cellulose and cellulose derivatives, as well as conventional plastic blends such as polyethylene. Such materials have the disadvantages of inadequate durability, poor mechanical properties and inability to fully biodegrade, especially when blended with conventional plastics. Starch derivatives, in particular materials using high degree of substitution and suitable plasticizers (DE 41 14 185) and modified starch derivatives, are readily thermoplastically processed and used in injection molding, melt-spinning or film making. However, these materials are again known to be brittle.

According to German Patent Publication No. 43 26 118, modified brittle starch esters having a degree of substitution of <3, preferably of 1.8 to 2.6 and polyethylene glycol (PEG) can be used to prevent such brittleness. It is said. According to German Patent Publication No. 44 18 678, blends obtained from starch esters and polyalkylene glycols having a degree of substitution of <3 have increased melt stabilization and their biodegradability is aliphatic, saturated or unsaturated dicarboxylic acids. And / or the biodegradability is said to be improved by the addition of oxydicarboxylic acid and / or oxytricarboxylic acid.

However, such blends are molded from water stability, mechanical properties, in particular elongation, impact resistance and barrier properties (blocking resistance), in particular injection molding, deep drawing, melt-spin processes, extrusion processes, in particular films. In the case of the composition is inappropriate.

Packaging materials for tobacco and other tobacco products are known to be made of many different designs and numerous other materials such as small wallets, cans and hinged lid boxes made of aluminum, tin, packaging or plastic. According to DEP 34 14 214 (US Pat. No. 53,79,889), the most widely known packaging for tobacco is a hinged lid box. This package can achieve the protection required by its contents by a multi-layer combination of various materials. It often consists of an inner layer, which is a back or printed aluminum foil, in most cases a layer of cardboard or paper with specifications printed on it, which is closed to the outer layer, closed with a package of thermally weldable films such as, for example, polypropylene. (Patent Publications 30 27 448 and 28 44 238 of the Federal Republic of Germany). Other packaging for cigarettes can protect their contents from deformation, loss of fragrance and humidity by the combination of tin (ie metal plates) and other materials such as paper, as in EP 087 483. .

However, these packages are also said to constitute exclusively thermoplastic films (German Patent Publication No. 42 26 640).

In order to improve the mechanical properties, gas and water vapor permeability of the thermoplastic film used as a tobacco packaging material, biaxially stretched polypropylene or polyalkylene terephthalate is used and metal deposition is possible. 36 32 376, EP 454 003 and EP 317 818).

All these solutions have drawbacks in the protection of the contents as well as water vapor, and gas resistance can be achieved by selecting materials consisting of at least one aluminum foil, tin foil or biaxially stretched plastic film. The necessary specifications are mostly printed on the packaging, tin or paper packaging used in the combination. Such complex packaging requires significant costs not only for the packaging materials used to maintain the quality of the packaged products and to attract the packaging, but also for their manufacture.

After use, packaging materials are usually disposed of, leaving environmental pollution problems. They decompose but do not degrade very slowly or at all under burial and natural climatic conditions. In general, when a regeneration process is required, it must be separated first. Such a separation process can be performed but generally cannot be complete. Moreover, this process is counterproductive, for example by water pollution in the process. Reuse of packaging materials cannot be reused for food law reasons.

Brief Description of the Invention

The present invention aims to further improve the properties of Deutschland Patent Publication Nos. 43 26 118 and 44 18 687, by improving the water stability, mechanical and barrier properties of the blend and without significant technical investment. It is possible to develop and reduce the weight of various types of packaging materials consisting of single or more layers of thermoplastic modified materials, and to print with excellent barrier properties against water vapor and gas without additional finishing or processing, It is furthermore aimed at using a fully biodegradable, technical recycling process and not adversely affecting the general recycling process.

This problem can be solved by the present invention as defined in the claims.

[Brief Description of Drawings]

1 shows a tobacco packaging material composed of an inner layer cardboard packaging and an outer layer packaging of a film according to the present invention.

2 shows a tobacco packaging material made of a single layer material.

Figure 3 shows a tobacco packaging material made of cardboard material trapped with the material according to the invention.

4 shows a portion of the packaging material of FIG.

Detailed description of the invention

The blends according to the invention have a molar mass of 200 to 1000 g / mol, preferably 200 to 60 g / mol, with starch esters which are predominantly starch acetates with a degree of substitution of <3, preferably between 1.8 and 2.6. Blended with polyethylene glycols (PEGs), saturated dicarboxylic acids and / or oxy containing up to 2 to 10 carbon atoms in a ratio of 100: 2 to 1000: 1 relative to the polyfunctional carboxylic acid. Conventional additives, in particular fillers, as well as aliphatic polycarbonates and plasticizers are blended together with or without dicarboxylic acid and / or oxytricarboxylic acid.

The aliphatic polycarbonate is a polymer containing a carboxylic acid ester group and has the following structural formula.

Here, R ₁ and R ₂ may be the same as or different from each other as hydrogen or a straight or branched C ₁ to C ₄ alkyl group, and may be connected to each other, and n is 250 to 10,000, preferably 350 to 3000. Particular preference is given to the use of polyethylene and polypropylene carbonate. Aliphatic polycarbonates can also be used as copolymers or terpolymers of polyalkylenes.

As a plasticizer, biologically compatible compounds can be considered, that is, monoesters and diesters of polyethylene glycol with C ₁ to C ₁₀ carboxylic acids such as polyethylene glycols, triethylene glycol diacetate and glycerol triacetate. . In addition, phthalic acid esters with C ₁ to C ₁₀ alkanols such as dimethyl phthalate, diethyl phthalate or dibutyl phthalate can be used. The ratio of starch acetate blend and aliphatic polycarbonate is 5: 95-95: 5, but the preferable one is 30: 70-70: 30. The content of the additive or plasticizer is 0 to 30%, preferably 0 to 15%.

These additives do not adversely affect the barrier properties and blend strength for packaging materials.

In thermoplastic processing, in particular, starch acetate having a degree of substitution of <3 and a polyalkylene glycol to which dicarboxylic acid and / or oxydicarboxylic acid and / or oxytricarboxylic acid are added are mixed in advance and this premix Extruded and granulated and then processed the granules with appropriate aliphatic polycarbonates and additives.

In this method, thermoplastic molding compositions can be produced by all conventional processing methods, such as, for example, injection molding, deep drawing, melt-spin processes. Such molding compositions are fully biodegradable and have an increase in water stability, in particular good mechanical properties with films, increased elongation and good barrier properties associated with gas and water vapor.

For surface design involving the promotion of beautiful printed matter, at least 35% of suitable fillers, such as calcium carbonate, talc, dry gypsum or kaoli, based on the total mass, can be mixed into the film. The amount of filler is preferably 1-30% by weight.

With respect to water vapor and gas, especially air, it can be seen that the single layer packaging has particular advantages, due to the excellent barrier properties of the film, without further treatment by biaxial stretching or metal vapor deposition. This is a supplementary packaging for general sales packaging, additional exterior packaging, cargo packaging or reusable packaging systems. The single layer packaging of the embodiment of the packaging of the present invention can reduce the production cost and the high investment costs associated with the packaging material while maintaining overall quality protection of the packaged product. However, for packaging that meets particularly high mechanical demands, it is also possible to simultaneously adopt a multilayer film type composed of different compositions depending on their location. The biodegradability and compostablility of the packaging film claimed as the right of the present invention is superior in that it degrades completely when stored under unconditional conditions for several weeks.

Using known processes for the recycling of these objects will be successful.

The following examples illustrate the advantages of the blends according to the invention.

The solid starting components of each composition were simply premixed in a high speed mixer. Next, a liquid plasticizer was added to the blend dried in powder form. It was processed into granules using an extruder and subsequently injection molded or extruded into a film on a standard bar (IS0, 80 mm × 10 mm × 4 mm) set by the International Organization for Standardization.

Table 1 Summary of Selected Base Formulations Resulting

Note) ⁽¹⁾ in Plast. ^II is dimethyl phthalate, and ⁽²⁾ is triethylene glycol diacetate.

The degree of acetylation of starch is 2.26 in ⁽³⁾ and 2.24 in ⁽⁴⁾ .

Stac = starch acetate, PEG = polyethylene carbonate

PPC = polypropene carbonate PEG = polyethylene glycol

In the blends according to the invention, one advantage is that fillers can be incorporated easily, and the cost advantages as well as some mechanical properties can be improved.

TABLE 2 Basic Formulation with Fillers

ISO bars were made from the compositions 1, 2, 3, 4 and 8 and the mechanical properties were measured.

Table 3 Mechanical Properties of ISO Bars

*: 100% non-destructive, BIH: steel ball indentation Hardness 30 (Ball Indentation Hardness).

It can be clearly seen that the properties vary widely, in particular composition 4 being unsuitable for injection molding. Such compositions are more useful for film applications.

Table 4 Mechanical Properties of Extruded Films

Measuring conditions :

Width: 15mm

Film dispensing direction: 1 longitudinal, t transverse

Measuring length: 50 mm

Test speed: 100 mm / min

Initial Force: O.1 N

Example of application as a packaging material:

Single layer tobacco packaging was made from several different kinds of films, the composition of which is shown in Table 5.

TABLE 5 Composition of substance

Dry blends of the compositions for Examples 1-3 of Table 5 were processed into granules in an extruder and subsequently extruded or blown into a film. Table 6 shows the transmission characteristics and the measured mechanical values of the film.

[Table 6] Mechanical and Transmission Properties

The film composition obtained by the composition of the substance by Examples 1-3 can be bonded easily. The measured strength properties of the film have been shown to be very good for tobacco products, especially tobacco packaging, and will protect the packaging contents from shipping, storage and handling damage. The measured transmission values could be achieved without the anisotropic stretching of the film. For biodegradability testing, empty packages with the above compositions were treated in industrial compost plants under decay conditions. The conditions of the packaging were examined weekly and the time was determined after the shape of the film mass could no longer be identified.

[Table 7] Corruption Time

Subsequently, among the packaging materials manufactured from the material according to the present invention, a cigarette packaging material will be described in more detail with reference to the drawings.

For example, the inner packaging 10 is provided in the form of a cigarette pack made of a conventional cardboard material. The cardboard material is composed especially of cellulose containing ordinary cardboard. These materials have a relatively high vapor permeability. This inner wrapper 10 is surrounded by tobacco completely contained therein. The lid 13 has a conventional separation seam 12 or a cut seam for the lid 13 to be raised.

The inner packaging 10 is wrapped by an outer packaging 11 made of the material according to the invention described above. The outer packaging material 11 consists of a thin film, preferably a transparent film, which wraps around the inner packaging material 10 and is foldable along the narrow side. On the front side, the outer packaging material 11 is sealed by ground 15. In addition, a "grabbing strip" 16 is provided, which wraps around the outer packaging 11, which is bounded by two weak lines 17. After tearing the 16 lines of "grabbing strip", the upper lid of the outer wrapper 11 can be removed, as the inner wrapper 10 is exposed to open the lid. All seams and grounds of the outer packaging material 11 can be sealed with steam resistance.

In the example of FIG. 2, it is the overall tobacco packaging material represented by the packaging material 20 of a single material composed of the material of the invention having a thickness of at least 100 μm, preferably 120 μm. Said single material packaging 20 also has a rectangular shape. The packaging material overlaps at the longitudinal weld seam 21 and the overlap is sealed. On the front side, the packaging material is placed on top of it by ground 22 and the overlapping layers are sealed. In addition, the monolithic tear strip 23 is bounded by a weak line 24 and unwound once around a portion of the packaging on the front side.

Thus, the packaging according to FIG. 2 is further comprised of a single layer of vapor resistant material that contains tobacco without an inner packaging. After tearing off the tearing strip 23, the end of the cigarette is immediately exposed.

In the example of FIGS. 3 and 4, the packaging material 30 is also a packaging material of a single material but differs only in two layers and has a cardboard material 31 which is later composed of the film 32 according to the invention. The outer shape of the package 30 is the same as the single material package 20 of FIG. 2.

The packaging material of the present invention need not be limited, but may be used for the packaging of various materials including foodstuffs, cosmetics, detergents, paper tissues, toilet articles. This packaging film is useful for the packaging of articles with similar packaging conditions to those requiring protection of the package contents, water vapor and gas resistance.

While certain preferred embodiments of the present invention have been described in detail, those skilled in the art will be able to modify or add various embodiments within the spirit and scope of the invention. Therefore, the present invention will be limited in part by the appended claims and applicable law borders.

Claims (17)

a) a blend of starch esters based on starch having a degree of substitution of 1.5 to 3 and having an aminopectin content of 20 to 80% by weight and at least one polyalkylene glycol having a molecular weight of 200 to 2,000, wherein said starch ester and poly Blends having an mixing ratio of alkylene glycol of 10: 1 to 10: 5 parts by weight, b) at least one aliphatic polycarbonate blended with the blend at 95: 5 to 5:95 parts by weight and having the formula

Wherein R ₁ and R ₂ are hydrogen or a C ₁ -C ₄ straight or pulverized alkyl group, n is 250-10,000. c) esters of phthalic acid with C ₁ to C ₁₀ n-alkanols, monoesters of polyethylene glycol with C ₁ to C ₁₀ carboxylic acids, diesters of polyethylene glycol with C ₁ to C ₁₀ carboxylic acids and their A biodegradable plasticizer, selected from the group consisting of combinations, not more than 30% by weight (but not including 0) to the total weight, and d) Biodegradable thermoplastic modified materials containing up to 35% by weight (but not including 0) of the total weight. The biodegradable thermoplastic modified material according to claim 1, wherein the mixing ratio of the aliphatic polycarbonate and the blend is 30:70-70:30. The biodegradable thermoplastic modification material of claim 1, wherein the plasticizer is an ester of phthalic acid with C ₁ to C ₁₀ n-alkanols. The biodegradation method according to claim 1, wherein the plasticizer is selected from the group consisting of a monoester of polyethylene glycol with C ₁ to C ₁₀ carboxylic acid, a diester of polyethylene glycol with C ₁ to C ₁₀ carboxylic acid, and a combination thereof. Thermoplastic Modifiers. The biodegradable thermoplastic modifying material of claim 1, wherein said aliphatic polycarbonate is polypropylene carbonate. The biodegradable thermoplastic modifying material of claim 1, wherein said aliphatic polycarbonate is polyethylene carbonate. The biodegradable thermoplastic modified material according to claim 1, wherein said aliphatic polycarbonate is a polyalkylene copolymer or a polyalkylene terpolymer. The biodegradable thermoplastic modified material of claim 1, wherein said starch ester is starch acetate. The biodegradable thermoplastic modified material according to claim 1, wherein the starch ester has a degree of substitution of 1.5 to 2.5. The biodegradable thermoplastic modified material according to claim 1, wherein the aliphatic polycarbonate has a degree of polymerization of 200-5,000. The at least one acid of claim 1, wherein the blend is selected from the group consisting of C ₂ -C ₁₀ aliphatic unsaturated dicarboxylic acids, C ₂ -C ₁₀ aliphatic saturated dicarboxylic acids and C ₂ -C ₁₀ oxydicarboxylic acids. The biodegradable thermoplastic modified material further containing and the mixing ratio of the said blend and an acid is 100: 2-1000: 1 weight part. 5. The biodegradable thermoplastic modified material of claim 4, wherein said biodegradable plasticizer is selected from the group consisting of triethylene glycol diacetate, glycerin triacetate and citric acid trialkyl ester. A packaging material made from the biodegradable thermoplastic variant material according to claim 1, wherein the packaging material is in the form of a foil, a coating or a combination thereof. The packaging material according to claim 13, wherein the packaging material is a single layer. 14. The packaging material according to claim 13, wherein the packaging material is selected from the group consisting of recycled packaging materials, sales packaging materials, repackaging packaging materials, transport packaging materials, and portions of these packaging materials. The packaging material according to claim 13, wherein the packaging material is a packing material for packing cigarettes. The packaging material according to claim 13, wherein the packaging material is a packaging material for packaging a product selected from the group consisting of food, cosmetics, cleaning materials, paper tissues, and toilet articles.

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